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Tubbed357 03-19-2010 08:12 PM

Rod Bearing Wear
 
I tore down my motor the other day and found that a few of my rod bearings had wore very fast and irregular. Last summer i threw this motor together on a very tight budget. So i figured id do another rebuild but this time the sky is the limit haha. Anyway the bearing has a copper color wear spot in one end and almost like a polished look around the rest. I dont have a picture of my actual bearing atm. But i found a pic of the exact same look that mine had. My bearing looks exactly like the bearing in the middle of the pic:
http://img246.imageshack.us/img246/9...ious026lw5.jpg[/URL]
The crazy thing is that my motor had less than 10 miles on it and it was fresh. The bearings looked like they had a good 100,000 miles on em haha. Im guessing its my crank or my rods are out of round but i need some advise from the pro's. Thanks guys

DoubleVision 03-19-2010 08:20 PM

After the block was honed, did you scrub the bores to get the hone grit out of the cylinder? Many think a simple wash job with soap gets it out but it don`t.

32Essex 03-19-2010 08:29 PM

Mike the crank and see if it's due a trip to the machine shop.

Tubbed357 03-19-2010 08:39 PM

Iv got another crank im going to use this time but i will get my newer crank checked also. I did clean the bores they were pristine. But i wasn't to clean about the assemble procedure so some grit might have gotten stuck on the bearings ha.. live and learn i guess. This time i will have my garage like a hospital :D

cobalt327 03-19-2010 09:16 PM

Looks like a bearing w/a lot of eccentricity to it, or improperly sized rod big ends, possibly a lot of idle speed/low speed use, w/less than optimum oil pressure or excessive cranking w/out start up.

Were both halves the same? If it was more the bottom, you might have had some detonation- especially if the bearings were loose in the cap half when you removed them.

Tubbed357 03-19-2010 09:31 PM

everything you explained is what this motor went through. The first time i attempted to fire her up i had the firing order wayyy wrong. It was running like complete crap and was barely staying running. Then i realized how big of a mistake i made with the firing order and switched everything so it was right.. So during that period it saw LOTS of detonation. It also saw LOTS of idling because i was having many issues with the tuning side of things or so i thought. Was probably the old heads and cam. It also had very low oil pressure that was the main reason for this rebuild not to mention i just wanted to do things right this time. So what would you say was the issue. A combo of all those. Ohh and yes it was only worn on the one half.

cobalt327 03-19-2010 09:41 PM

What are your plans for it this time?

Tubbed357 03-19-2010 10:29 PM

Well this time im going for a high compression pump gas friendly 357. somewhere around 11:1 hoping to have one nasty street car. I have a decent set of small chamber heads with big valves. Im going to be going with the XE284 cam. At first i was gong to get a thumpr but i realized they really are not a power based cam, more for just sound ha. Should be one nice motor when im done this time :) the block is going to the machine shop next week along with the heads. Still need to get the stall but its coming. Any tips you could give me as far as building a nasty street motor. Thanks again

cobalt327 03-19-2010 10:41 PM

Quote:

Originally Posted by Tubbed357
Well this time im going for a high compression pump gas friendly 357. somewhere around 11:1 hoping to have one nasty street car. I have a decent set of small chamber heads with big valves. Im going to be going with the XE284 cam. At first i was gong to get a thumpr but i realized they really are not a power based cam, more for just sound ha. Should be one nice motor when im done this time :) the block is going to the machine shop next week along with the heads. Still need to get the stall but its coming. Any tips you could give me as far as building a nasty street motor. Thanks again

Sounds like a plan. Only don't get to carried away w/CR unless you have a good supply of high octane fuel. An iron head will tolerate maybe 10:1 CR w/premium and the right cam. A fast burn head like the Vortec might tolerate a bit more than that w/o issues. Too much and it gets detonation prone w/o a LOT of cam and/or race fuel.

When you get ready to start w/it, why not start a thread on the engine and what you specifically want to do w/it. That way, everyone will see it and you'll get a good response.

And good idea to pass on the Thumper. There are better performing cams available, IMO.

Tubbed357 03-20-2010 12:35 PM

Quote:

Originally Posted by cobalt327
Sounds like a plan. Only don't get to carried away w/CR unless you have a good supply of high octane fuel. An iron head will tolerate maybe 10:1 CR w/premium and the right cam. A fast burn head like the Vortec might tolerate a bit more than that w/o issues. Too much and it gets detonation prone w/o a LOT of cam and/or race fuel.

When you get ready to start w/it, why not start a thread on the engine and what you specifically want to do w/it. That way, everyone will see it and you'll get a good response.

And good idea to pass on the Thumper. There are better performing cams available, IMO.

Yes you are right about the thumper cams. There are better out there. The heads i have are some nice iron centerbolt heads with 64cc chambers. The valves are 1.94-1.5

Do you think it would be a bad idea to run 11:1 on these heads. Im going to get them milled very soon here so my chambers will be in the 58cc area. Also i do have high octane available at the pump right near me.

stroker_SS 03-20-2010 01:16 PM

Looks like you had a lot of particle contamination. I would think that lack of oil or incorrect parts fitment would have caused a little more of a burnt or bluish coloring.

Plaintoast 03-20-2010 01:51 PM

Quote:

Originally Posted by Tubbed357
Yes you are right about the thumper cams. There are better out there. The heads i have are some nice iron centerbolt heads with 64cc chambers. The valves are 1.94-1.5

Do you think it would be a bad idea to run 11:1 on these heads. Im going to get them milled very soon here so my chambers will be in the 58cc area. Also i do have high octane available at the pump right near me.

Any idea what the casting number is on those centerbolt heads?

Tubbed357 03-20-2010 05:17 PM

Quote:

Originally Posted by Plaintoast
Any idea what the casting number is on those centerbolt heads?

Sure do. its 14096217 they are pretty new heads, think they were used in crate motors a while back. I agree with the particle contamination and low oil pressure. Ill make sure i Plastigage all the journals :) Ill probably be starting the build in a week or so so ill let you guys know how it goes. I mean i was having serious issues with my oil pressure. On a cold start i would have a good 25-30 but when it was warmed up completely iv seen it as low as 3-5 at idle. I wont have these issues this time around but what could have caused this for future reference. I was thinking big clearances or something i was missing not sure.

cobalt327 03-20-2010 08:04 PM

IIRC, those heads have the dual intake (72 and 90 degree) center intake bolt holes.

They're decent heads- were used on the discontinued 300 HP 350 HO crate engines up until Vortec heads were used. The Vortec heads bumped the HP to 330 on the HO engine- although I'm not positive ALL other specs were the same.

Start a fresh thread on the engine build- that way it'll get better exposure.

Tubbed357 03-20-2010 10:17 PM

Quote:

Originally Posted by cobalt327
IIRC, those heads have the dual intake (72 and 90 degree) center intake bolt holes.

They're decent heads- were used on the discontinued 300 HP 350 HO crate engines up until Vortec heads were used. The Vortec heads bumped the HP to 330 on the HO engine- although I'm not positive ALL other specs were the same.

Start a fresh thread on the engine build- that way it'll get better exposure.

I might haha. But can i run 11:1 on these heads. I dont see why not really :D but some times i miss things ha


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